[1] Childrens Environm Hlth & Dis Prevent Res Ctr, Hanover, NH 03755 USA
[2] Geisel Sch Med, Dept Community & Family Med, Sect Biostat & Epidemiol, Lebanon, NH 03756 USA
[3] Geisel Sch Med, Norris Cotton Canc Ctr, Lebanon, NH 03756 USA
[4] NYU, Sch Med, Dept Populat Hlth, New York, NY 10016 USA